Indian jeweller Nirav Modi is wanted for his alleged role in a $1.8 billion bank scam.
(REUTERS)

Federal officials in India have launched a massive manhunt for a billionaire jeweler - who made pieces for A-list celebrities like Kate Winslet and Naomi Watts - for his alleged role in a $1.8 billion bank scam.

India’s Central Bureau of Investigation launched a global manhunt for diamond billionaire Nirav Modi, who authorities said allegedly cheated the state-owned Punjab National Bank by using fake bank "letters of understanding" to get loans.

Modi has not yet been charged with a crime.

Indian media reported that Modi and his family are hiding in New York or Dubai. The External Affairs Ministry said it has suspended the passports of Modi and his uncle, Mehul Chinubhai Choksi, for four weeks.

According to Sky News, officials have seized more than half a dozen luxury cars including a Rolls Royce Ghost and a Porsche Panamera from the billionaire and his companies, along with around $873,000 worth of jewelry, gold, diamonds, precious metals and stones.

On Tuesday, India's federal investigating agency arrested five executives who worked for the companies owned by Modi and Choksi.

Five bank executives and another employee of Modi's company Firestar group were arrested over the past three days for allegedly conspiring to cheat the bank.

Such scams, he said, not only had a direct cost to the country and the taxpayers, but also an indirect cost to borrowings and development.

The Press Trust of India news agency reported that Modi sent a letter to the bank this week saying he owes less than half the amount claimed by the bank in connection with the alleged fraud.

Modi runs an international jewelry empire that reaches from India to New York, with a string of high-end brands. He and his family fled India weeks before the bank registered a criminal case with the CBI on Jan. 31.

In his letter to the bank, Modi said he owes about 50 billion rupees ($775 million), according to PTI. He said the $1.8 billion cited by the bank had resulted in a media frenzy that pressured authorities to quickly search and seize assets from his Firestar International and Firestar Diamond International companies.

"This thereby jeopardized our ability to discharge the dues of the group to the banks," Modi said.

The CBI spokesman said the agency had not yet received Modi's letter. There was no immediate comment from the state-run bank.

The Associated Press contributed to this report.

Lucia I. Suarez Sang is a Reporter for FoxNews.com. Follow her on Twitter @luciasuarezsang